Topochemical lithium deintercalation of main-group oxide anion-redox cathode materials

Li-ion batteries, based on complex transition-metal oxide cathodes have become essential, energy-dense, rechargeable power sources for a wide range of electronic devices. It has been proposed that by harnessing the redox activity of the oxide anions in these materials (in addition to the metal cations) the energy storage capacities of cathode materials can be enhanced. To investigate this possibility we have prepared a series of ‘model’ compounds which only exhibit anion redox activity, so we can more easily study the nature of the ‘oxidized anion species’ present. We propose to collect neutron powder diffraction data from a series of de-lithiated anion-redox cathode materials, to better understand how their crystal structures evolve as lithium is extracted from them, both in terms of lithium-vacancy ordering and the possible formation of [O2]2- peroxide ions within the material.